A work vehicle such as a motor grader, bulldozer or the like typically includes a roll-over protective structure (ROPS) to comply with governmental safety regulations. In the case of a work vehicle having an enclosed operator cab, the ROPS is typically incorporated into the framework of the cab. More particularly, the cab typically includes corner posts supporting an overhead roof, and safety glass spanning between the corner posts allowing visibility by an operator. The corner posts are single piece corner posts which are sized and configured to withstand roll-over requirements. The one piece nature of the corner posts results in the work machine having a fixed overall height.
Most new work vehicles such as agricultural tractors that do not include an operator cab have a ROPS in the form of an upside down U-shaped frame which extends above the height of the operator when seated. To allow the tractor to be used in buildings having lower doorways or along overhanging tree limbs, the ROPS may be folded rearwardly about mid height of the ROPS, thereby decreasing the effective height of the ROPS. Such an arrangement obviously cannot be used to fold over an operator cab.
For one application, it is desirable for a motor grader unit to be field-altered such that the overall height of the machine can be less than 102 inches tall. The machine must be able to be operated in this condition so that it can be driven onto a cargo plane for air transport. For example, when such a work machine is used in support of military operations, it may be desirable to load the work machine onto a C-130 air cargo transport plane for transport to a selected location. The rear loading ramp and door opening have a maximum height of 102 inches, resulting in the overall machine height requirement specified above. Parts of the machine can be disassembled and shipped on a skid separate from the rest of the machine for this operation. When the machine is fully re-assembled, it must meet ROPS safety requirements according to ISO 3471.
What is needed in the art is an operator cab having a ROPS which may be quickly and easily altered to decrease the overall height of the vehicle, particularly for use during transport of the work vehicle.